Donor assembly

ABSTRACT

AN ELECTROSCOPIC MARKING PARTICLE SUPPLY AND DONOR ASSEMBLY HAVING A CYLINDRICAL HOUSING WITH AN OPENING THEREIN TO MAKE ACCESSIBLE TO ANOTHER MEMBER A CRESCENTIC TUBULAR MEMBER ENCLOSING A SUPPLY OF DEVELOPER MATERIAL AND WHICH RECIPROCATES INSIDE THE HOUSING AND ABOUT THE AXIS THEREOF.

W. D. PERUN DONOR ASSEMBLY Sept. 21, 1911 Filed March 10, 1969 mvmwomWILLIAM D. PERUN BY 2 a a AT7DRNEY United States Patent 01 ice 3,606,864DONOR ASSEMBLY William D. Perun, Webster, N.Y., assignor to XeroxCorporation, Rochester, N.Y. Filed Mar. 10, 1969, Ser. No. 805,767 Int.Cl. G03g 13/00 US. Cl'. 118-637 11 Claims ABSTRACT OF THE DISCLOSUREThis invention relates, generally, to apparatus for supplyingpredetermined amounts of electroscopic marking particles and,specfically, to donor assemblies used to load electrostatic latent imagedeveloping apparatus.

The varied applications to which the principles of electrostaticrecording have been directed have exacerbated the operationalrequirements of the developer assemblies used to make the recordingsvisible. One direct reason for this is the requirement of mobilityplaced on certain electrostatic recorders. Great mobility impliesanything but a normal fixed orientation of the parts of the recorder.Gravity forces no longer can be considered effective from a singledirection. Mobility also implies compactness, reliability, and a minimumof parts. Periodic maintenance preferably should also be expedited bythe design of the recorder and the quality of its recordings cannot becompromised.

In addition, prior art developer assemblies have presented a problem ofinsufficient agitation of the developer material creating poor qualityand inconsistencies in the developed recording.

Therefore, it is an object of the present invention to improvedevelopment of electrostatic charge patterns with electroscopic markingmaterial.

It is another object of the present invention to provide an improved,low-cost, very compact developer donor assembly.

A still further object of the present invention is to provide animproved donor assembly which is easily maintained and self-agitating.

These objects and others not specifically mentioned will become moreapparent when the following detailed description of the presentinvention is read in connection with the appended drawings wherein:

FIG. 1 is a front view of the present invention with some parts brokenaway along with a source of motive drive;

FIG. 2 is a cross-sectional view of the present invention as seen atsection 22 in FIG. 1; and,

FIG. 3 is a perspective view of one end of the present invention showingone source of motive drive therefor.

Before reference is made to a detailed description of the drawings, abrief mention of the utility of the present invention may be helpful inbetter understanding its objects and features. In the art ofelectrostatics wherein it is desirable to render latent electrostaticcharge patterns visible by the deposition thereon of electroscopicmarking particles, it is necessary to convey such marking particles tothe pattern. This conveyance can be accomplished by various apparatuswith which the present invention is compatible and, for illustration, anatural fur applicator or brush will be considered. The triboelectricrelationship between the applicator and the electroscopic markingparticles, or toner as they are conventionally referred to, is

3,606,864 Patented Sept. 21, 1971 such that when placed in contact witheach other the applicator attracts the toner. Movement of the brush thusloaded with toner across the electrostatic charge pattern results inthis pattern attracting the toner from the applicator thereby developingor rendering the pattern visible. In order to make this developmentcycle efliciently repetitive at a high rate, it is necessary toconveniently and effectively load the applicator with toner in a mannerto replenish those areas of the applicator from which toner has beenremoved by the attractive force of the charge pattern. The system whichserves this function is called a donor assembly and it is this assemblyto which the present invention relates.

Reference will now be made to FIGS. 1, 2, and 3 wherein like referencenumerals refer to like elements. A cylindrical housing 2 forms the outerdimensions of the donor assembly in accordance with the presentinvention. This housing may be made of a non-metallic or insulativematerial and have any desirable dimension. In the outer surface of thishousing there is located an opening or slot 4 the sides of whichparallel to the axis of the housing subtend an angle of approximatelydegrees. As shown, the housing 2 has two end plates 6 and 8 which arefixed respectively to two plug members 7 and 9. A hearing 10 passesthrough the center of each end plate and plug member and is supportedthereby.

On the inside of the housing 2 there is mounted for rotationconcentrically with the axis thereof a crescentic member 14 which isbest shown by its cross-sectional configuration illustrated in FIG. 2.This crescentic member 14 is tubular or cylindrical in form and hasalong its axial length a slot or opening 16 the edges 18 and 19 of whichsubtend an angle with its center of rotation, for

example, of approximately sixty degrees. As shown in FIG. 2, the edges18 and 19 of this opening 16 are bevelled for purposes which will beseen more clearly hereinafter. The crescentic member 14 has an exteriordiameter less than the interior diameter of the housing 2 and may becomprised of a conductive sleeve having an insulative coated exterior.This member 14 has attached to its ends terminal members 24 and 26, theformer being mechanically coupled to a shaft 12 which passes through andcooperates with bearing 10 to translate a rotative force to the member14. The other terminal member 26 is attached to a shaft (not shown)which passes through and cooperates with bearing 10 to permit thecrescentic member 14 to rotate freely within housing 2.

The bearings 10 are isolated from the volume defined by terminal members24 and 26 and the interior surfaces of housing 2 by two O-ring seals 25which may be of any suitable material such as polyurethane. These sealscooperate and mate with the plug members 7 and 9 to provide a bearingsurface for the crescentic member 14 as it rotates.

The shaft 12 is attached to a source of motive power 28 via a mechanicalcoupling 30 of conventional design. The motor 28 may be a permanentmagnet synchronous type or an inductor alternating current type. As anexample only, a Haydon General Times Series MP20 inductor AC. 4 r.p.m.motor has been utilized successfully. Input leads 32 may be used toprovide suitable electrical power to the motor 28.

As shown best in FIGS. 1 and 3, fixed to shaft 12 is a collar 34 havinga pin 36 extending radially therefrom relative to the shaft 12. The pin36 has an axial dimension sufiicient to contact stop member 38 at twostopping surfaces 40 and 42 as the shaft 12 is rotated in eitherdirection.

The stop member 38 and the pin 36 cooperate to control the motor 28 tooperate in a reciprocating or reversing mode. The types of motorshereinabove specified can be made to mechanically oscillate when theirno-back system is removed. This system is generally composed of a stepno-back gear on the rotor running against a special tooth-formed idlergear. This combination permits free rotation in the desired directionbut prevents motion in the reverse direction. If this no-back system isomitted, the motor can start and operate in either direction if it issupplied with two mechanical stops. These stops are provided by thesurfaces 40 and 42 of stop member 38. In operation what occurs is themotor will proceed in one direction until pin 36 abuts one of the stopsurfaces. The motor will momentarily stall and reverse its direction ofmovement in the opposite direction until it reaches the other stopsurface. This cycle is repeated creating a reciprocating drive force onthe shaft 12 and ultimately the crescentic member 14.

From FIGS. 2 and 3 is can be realized that the stop surfaces are sopositioned relative to each other and the slot 4 in housing 2 to controlthe ultimate position of leading edge of the crescentic member 14.Therefore, for example, as pin 36 approaches stop surface 42, edge 18approaches seal 20 as the upper limit on its movement toward opening 4.The stop surfaces are established relative to these edges 18 and 19 toinsure that neither edge will be moved past either seal 20 or 22.

As best shown in FIG. 2, the donor assembly of the present invention maybe filled t approximately half of its volume or completely filled with aconventional developer which may be a suitable mixture of carriermaterial and toner. As shown, the developer 44 generally fills thevolume created inside the cylindrical housing 2 by the crescentic member14. Some of the developer material succeeds in filling the space betweenthe outer surface of the crescentic member 14 and the interior surfaceof the cylindrical housing 2. As the crescentic member 14 is made torotate through a specific angle, such as 180 degrees for the stopsurfaces as shown, the developer material is agitated with the bevellededges 18 and 19, the crescentic member can move more easily through thedeveloper material thereby increasing the agitation thereof.

In describing the operation of the present invention, it is helpful torefer to the exterior or donative surface of the crescentic member 14 asbeing composed of a first and a second area. The first area begins atedge 18 and extends toward edge 19 while the second area begins at edge19 and extends toward edge 18. Each of these areas overlap each othersince the extent of each from its respective edge is that are of thecross-section of member 14 equal to the angle through which member 14 isrotated in one cycle.

Assuming that the crescentic member 14 is in an initial position asdepicted in the drawings, when the motor 28 is energized member 14 willbe rotated in either of two directions. If this direction is such as tomove the crescentic member 14 in a counterclockwise direction as FIG. 2is viewed, then the first area of member 14 is moved through andenveloped by the developer material 44 while the second area is movedacross and positioned at opening 4 in housing 2. The pin 36 then abutsagainst stop surface 40 and the motor 28 reverses thereby rotatingmember 14 in a clockwise direction. This reversal withdraws the firstarea from the developer material 44 in the sump and moves it toward theopening 4. Both during its immersion into and withdrawal from the sump,the first area triboelectrically attracted toner to it. Just as thefirst area is withdrawn from the developer, the second area is movedthrough the developer wherein toner is triboelectrically attracted toit. As the pin 36 continues to move toward stop surface 42, the firstarea passes seal 20 which effectively rneters the toner layer nowadhering to the first area. As the toner ladened first area passes seal20 it moves into contact with another toner conveyor 46, which may be adeveloping applicator. As this contact continues, due to the rotation ofthe applicator 46 and crescentic member 14 toner may be transferred bytriboelectric attraction from the first area to the applicator.

The transferred toner may then be utilized in any of several ways suchas in rendering a latent electrostatic charge pattern visible.

When pin 36 strikes stop surface 42, the cycle is complete and the motorreverses as hereinabove described. The next cycle will bring the firstarea back into the developer where it will be replenished with toner andthe second area into contact with the applicator 46 at the opening 4 inhousing 2.

In order to insure consistent donation of toner to the applicator 46,two seals 20 and 22 are provided which may be of polypropylene. As shownbest in FIG. 2, each seal (20 and 22) is fixed to the interior surfaceof housing 2 and extends between seals 25 substantially parallel to eachother and to the edges of opening 4 which are parallel to the axis ofrotation of crescentic member 14. The dimension of each seal (20 and 22)in a radial direction relative to this axis is such as to elfectivelyallow only a predetermined substantially uniform layer of toner to passinto the donative zone formed by opening 4. In addition, these sealsalso insure that no carrier material is allowed to pass into this Zonewhich would be undesirable.

As can be seen from the foregoing description, the present invention hasa compactness which permits mobility and efficiency in operation. Whenthe toner supply is depleted, the housing 2 may be easily removed as asingle unit and a fully toner-charged donor assembly installed.

While a preferred embodiment has been described, variations inmechanical structure are possible within the basic concept of thepresent invention. For example, while certain angles have beenspecified, other angles may be employed in designing the openings inhousing 2, or the crescentic member 14, or the desired rotation ofmember 14. In addition, although a specific drive system for crescenticmember 14 has been detailed, other systems may also be suitable. Forinstance, an eccentric cam may be rotated to actuate a spring biassedrod coupled to the crescentic member 14 such that as the cam rotates themember 14 reciprocates through a predetermined angle. The crescenticmember 14 has been described as being conductive with an insulatingexterior coating. However, it is possible to use an insulative materialentirely. While the crescentic member 14 is preferably a cylinder with aslot running its entire length, it may also take the form of thecylindrical housing 2.

While a particular relationship between aperture 4 in housing 2 and theaxis of. housing 2 has been described, such an orientation may be variedwithout departing from the essence of the inventive concept. Forexample, the middle of opening 4 may be located at the position of seal20 as FIG. 2 is now depicted.

Further, the advantages and features of the present invention would notbe substantially compromised if the crescentic member 14 were rotatedonly in a single direction inside housing 2 instead of the previouslydescribed reciprocating action.

In addition, although the donor member 14 is shown having a slottherein, it is within the present inventive concept that another openingor series of openings of suitable configuration may be substituted forthis slot as long as they permit the developer to pass from the volumedefined by the donor member to the space between this member and theinterior of housing 2.

While the invention has been described with reference to a preferredembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof Without departing from the true spirit and scope of theinvention.

What is claimed is:

1. A powder dispensing apparatus comprising:

(a) a substantially cylindrical powder container having an elongatedopening in its surface generally parallel to its longitudinal axis;

(b) a generally cylindrical dispenser housing having a slightly largerdiameter than said container positioned concentrically outside saidcontainer said housing also having an elongated slot in its surfacegenerally parallel to its longitudinal axis;

() said container having an outer surface, comprising a material adaptedto pick up and carry a thin layer of said powder; and,

(d) means to oscillate said container within said housing so that powderin the container is gradually dispensed from within it and carried onits outer surface to the opening in said housing without the openings insaid container and housing coming into alignment with each other.

2. Apparatus as defined in claim 1 further including a powder applicatorpositioned outside said housing and supported in powder transferrelationship with the surface of said container through the slot in saidhousing.

3. A donor assembly for electroscopic marking particles comprising:

a housing member having a cylindrical surface equidistantly spaced froman axis and having an aperture therein defined by first and second edgessubstantially parallel to said axis;

a tubular member mounted for rotation within said housing member andhaving a surface substantially equidistantly spaced from said axis witha slot therein having third and fourth edges substantially parallel tosaid axis;

motive means for rotating said tubular member relative to said housingmember in a first direction until a predetermined proximity between saidfirst and third edges exist and in a second direction until apredetermined proximity exists between said second and fourth edges suchthat said aperture and said slot are prevented from becoming aligned;and

tWo seal means inside said housing and attached thereto, one of saidseal means extending proximate to and along each of said first andsecond edges.

4. An assembly for making a layer of electroscopic marking particlesavailable comprising:

a housing having a surface with an aperture therein;

a donor member having an outer surface subdivided into a first andsecond portion, said donor member mounted for relative motion insidesaid housing;

a supply of electroscopic marking particles in said housing;

motive means for alternately moving said first portion into said supplywhile moving said second portion to said aperture and moving said secondportion into said supply while moving first portion to said aperture;

seaid donor member being tubular and having a crescentic cross-sectionand said supply at least partially filling the volume defined by saiddonor member; and

means provided inside said housing for decreasing the space between saidhousing and said outer surface proximate the side of said of saidaperture transverse to the direction of movement of said donor member.

5. Developer apparatus comprising:

a housing having an opening therein;

a donor member storing developer internally thereof,

said donor being supported in said housing for movement relative theretoand comprising an opening and an outer surface capable of carryingdeveloper thereon;

means for moving said donor member whereby de- 6 veloper is dispensedthrough the opening therein and into said housing, with a subsequentmovement of said outer surface into cont-act with said developer andinto a position opposite the opening in said housing; and

a developer applicator positioned externally of said housing andsupported for movement in developer transfer relationship with saidsurface.

6. Apparatus according to claim 5 wherein,

said outer surface is subdivided into first and second portions, and

said means for moving said surface comprises means for reciprocatingsaid donor member whereby said portions are alternately moved intocontact with said developer and then opposite the opening in saidhousing without overlapping of said openings.

7. Apparatus according to claim 5 including means for reducing the spacebetween said housing and said outer surface proximate said opening insaid housing.

8. Apparatus according to claim 5 wherein,

said housing comprises a cylindrical surface and said donor member has atubular configuration, said housing and said donor member beingconcentrically supported and said housing having a slightly largerdiameter than said donor member, and

wherein said opening in said donor member comprises an elongated slotdelineated by a pair of beveled edges.

9. Apparatus according to claim 8 including, at least one seal meansinside said housing and attached thereto and extending proximate to andcoextensively with one of said beveled edges.

10. An assembly for making a layer of electroscopic marking particlesavailable comprising:

a housing having a surface with an aperture therein;

a donor member having an outer surface subdivided into a first andsecond portion, said donor member mounted for relative motion insidesaid housing;

a supply of electroscopic marking particles in said housing;

motive means for alternately moving said first portion into contact withsaid supply while moving said second portion to said aperture and movingsaid second portion into contact with said supply while moving saidfirst portion to said aperture; and

an applicator positioned externally of said housing and supported formovement in developer transfer relationship with said surface.

11. An assembly according to claim 10 wherein said donor member istubular and has a crescentic cross-section and said supply at leastpartially fills the volume defined by said donor member.

References Cited UNITED STATES PATENTS 2,620,946 12/1952 Auer 222-409X3,339,807 9/1967 Eichorn 118-637X 3,149,760 9/1964 Eichorn et a1. 2222383,337,072 8/1967 Del Vecchio et a1. 214304 MERV IN STEIN, PrimaryExaminer L. MILLSTEIN, Assistant Examiner U.S. Cl. X.R. 117-175; 222-238

